How should I run several air compressors together to cut electricity and CO2?

Run as few compressors as the demand needs: let one or more run fully loaded as base load, give one machine, ideally with a variable speed drive, the trim role, and switch off the rest. A sequencer does this automatically. The saving comes mostly from compressors that sit unloaded, drawing power while making no air.

Why partly loaded compressors waste power

A screw compressor on load and unload control keeps its motor turning when it unloads. It makes no air but still draws a real share of its full-load power, so measure that figure on your own machines rather than assuming it. When three machines share a demand that two could meet, each spends hours unloaded, and that power is pure loss.

Base load and trim roles

• Base load machines run fully loaded most of the time, where their kW per unit of air is best.
• One trim machine follows the swings in demand. A variable speed drive unit suits this role because its power falls with output.
• Spare machines stay off and start only when pressure falls below a set point.
• Do not put two variable speed units in trim together; they fight each other and both run at poor efficiency.

Sequencer settings that matter

1. Set one narrow pressure band for the whole system instead of separate bands on each machine, which cascade upward and raise system pressure.
2. Rotate the base load role every week or month to even out running hours.
3. Add enough receiver storage near the compressors so short demand peaks do not start another machine.
4. Fix leaks first: a sequencer that keeps an extra compressor running to feed leaks only automates the waste.

How to find the saving before you buy

1. Download loaded hours, unloaded hours and starts from each compressor's controller for a typical month.
2. Measure unloaded kW on each machine with a clamp meter, or take it from the maker's datasheet.
3. Unloaded kWh = unloaded hours x unloaded kW, for every machine.
4. Estimate how many of those hours a sequencer would turn into off time, and multiply the kWh by 0.710 kg CO2 per kWh.

Illustrative plant with three 55 kW screw compressors

• Controller logs show the third machine unloaded for 2,500 hours a year
• Measured unloaded power: 16 kW
• With a sequencer it stays off: 16 x 2,500 = 40,000 kWh saved a year
• CO2: 40,000 x 0.710 = 28,400 kg, about 28.4 t CO2 a year
• At an assumed tariff of Rs 8 per kWh: 40,000 x 8 = Rs 3.2 lakh a year

Hours, unloaded power and tariff are illustrative. Use your own controller logs and bills.

What Senseible does here

Senseible reads your electricity bills and diesel invoices into a monthly record of kWh, litres and CO2, so the change after a new machine goes in shows up month by month against the same bills. Machine-level meter feeds can be set up with the Senseible team.

• Compressed air leak cost and emissions
• Compressed air pressure reduction savings
• Air compressor heat recovery savings
• Energy transition savings calculator

Sources: BEE Guide Book 3, Energy Efficiency in Electrical Utilities, Chapter 3 Compressed Air System (capacity control), CEA CO2 Baseline Database, version 21.0

Last reviewed 2026-10-18.